Write a grading program that helps to determine your letter grade based on your exam score. For example, when you put in exam score of 80, the program will determine you get a B. Please note the following:
1) Your letter will be determined by only one exam score.
2) The program will keep on prompting you to put more scores until you hit the E button on your keyboard.
3) The scoring standard:
A 90 - 100
B 80 - 89
C 70 - 79
D 60 - 69
F Below 60
Analyze this problem, and write a pseudo code based on your analysis.